Three shipments of Moderna’s vaccine were delayed from distribution after it was discovered that they may not have maintained a stable temperature before arriving in Texas last week, Bloomberg first reported.
The three vaccine shipments were originally supposed to be delivered ahead of Christmas. However, it’s unclear how many total doses were affected by the temperature issue. The federal government has already replaced the shipments, the outlet also reported.
The Texas Department of State Health Services has also noted that the vaccine delays have created the perception that a small number of vaccine doses have been administered, although that is not the case, Bloomberg reported.
“Some of the shipments for week 2 were delayed and were not received by providers until Monday and Tuesday of this week,” health department spokeswoman Lara Anton told Bloomberg.
Problems with data systems used by hospitals to track shots given might also make the progress of vaccination seem slower than it really is.
“It’ll look like there’s [a] vaccine sitting on the shelf when it’s actually been administered,” added Carrier Kroll, vice president of advocacy, quality and public health at the Texas Hospital Association.
The Texas incident is not the first obstacle that the US has faced in its efforts to vaccinate 20 million Americans by the end of the year.
Earlier this month, 50 vials of the Moderna vaccine had to be disposed of at the Advocate Aurora Health medical center in Grafton, Wisconsin, after a hospital employee failed to return the vials to a storage freezer.
"We learned that about 50 vials of Moderna vaccine were inadvertently removed from a pharmacy refrigerator overnight," an Advocate Aurora spokesperson told TMJ4 at the time. "While some of the vaccine was administered to team members on December 26 within the approved 12-hour post-refrigeration window, unfortunately, most of it had to be discarded due to the temperature storage requirements necessary to maintain its viability."
According to the US Centers for Disease Control and Prevention (CDC), the vaccine must be stored at temperatures between negative 13 degrees Fahrenheit and 5 degrees Fahrenheit.
In an email to NPR, vaccine researcher Margaret Liu explained that the Moderna vaccine must be frozen to ensure that the mRNA, which gives instructions to cells to make a piece of the spike protein of the coronavirus, remains stable. The spike protein is found on the surface of SARS-CoV-2, the virus that causes COVID-19, and is used by the pathogen to enter cells.
"Everything happens more slowly as you lower the temperature," Liu explained.
"So your chemical reactions — the enzymes that break down RNA — are going to happen more slowly,” Liu added.
The US government has already purchased 200 million doses of the Moderna vaccine so far.